Pure Water Occasional, July 27, 2019
Water News in a Nutshell
Cities around the US are continuing to find elevated lead levels in residential water supplies. The city of Highland Park, MI, for example, reported levels considerably above the 15 ppb limit, in nine of thirty-six sites tested. The city is offering advice (including rinsing lines up to 15 minutes before using water) and access to pitcher-style water filters. The mayor said, "We will not sit by and become another Flint." More.
The state of Montana announced a plan that will test all schools in the state for lead.
Fort Lauderdale's Water Crisis: Failure of "A water plant held together by spit and chewing gum."
Excerpted from an editorial in the Fort Lauderdale News.
A water crisis that brought Fort Lauderdale to its knees this week further exposed the frailty of the city’s water/sewer system, spotlighting years of neglect that could leave the city in the same predicament at any time.
Lack of maintenance turned a manageable mistake into a system collapse that dried up faucets for tens of thousands of people and forced countless businesses to shut down.
A contractor for Florida Power & Light set off the situation when its workers drilled into a critical water main, but the fiasco could have been contained quickly. Had the system worked properly, officials acknowledged, water would have been diverted to another pipe, and few people would have known there was a breach.
Instead, underground valves that hadn’t been tested in years failed and created a crisis affecting some 220,000 people. Even after service was restored, residents were ordered to boil their contaminated water before consuming it.
City officials and observers said the water outage highlighted the importance — and inadequacy — of the Fiveash Regional Water Treatment Plant, which supplies most of the city’s drinking water. Built in 1954 and falling apart, it must be renovated for $144 million, or replaced, a consultant advised. If that’s not done in time, another crisis like Fort Lauderdale saw this week could occur.
In other water news,
Cities are questioning the wisdom of allowing the establishment of data centers because of their extremely high water consumption. Data centers typically use water to cool the computer servers and related technology that store massive amounts of digital information for companies such as Google, Facebook and Amazon.
India sent a spacecraft to explore water deposits on the far side of the moon. The craft is scheduled to land on the lunar south pole in September and send a rover to explore water deposits confirmed by an earlier, orbiting mission. India would become only the fourth nation to land on the moon, following the U.S., Russia and China.
The Aspen Times reports that Ruedi Reservoir and other Colorado waterways are facing an increased threat of infestation by invasive mussels that could interfere with the function of dams and irrigation systems. It’s not an issue that can be taken lightly, Colorado Parks and Wildlife says, because operators of reservoirs might be forced to close them to boating to protect their infrastructure. Statewide, inspectors have intercepted 51 boats infested with mussels this year — equaling the total for all of last year. More.
There were numerous other reports this summer of increasing Zebra mussel infestation of lakes and reservoirs.
RWI stands for Recreational Water Illness, and according to the Centers for Disease Control, diarrhea-causing RWIs have increased 200 percent since 2004. The number one rule for avoiding RWIs, even in chlorinated pools, is Don't Swallow the Water.
Of ten water samples taken in Montana this summer, nine contained some form of plastic. Of those, six contained fibers from clothing and fishing line, eight contained hard plastics and polystyrene, and three contained plastic film from bags or wrappers.
New Bedford, MA is engaged in an experimental program that uses bacteria that metabolize nitrogen to reduce nutrients in a pond in an effort to control overgrowth of algae and plants. Details.
Strange as it seems, fires can be started by water bottles. A clear plastic bottle of water left in direct sunlight in the seat of a car can produce enough heat to set the seat on fire in just a couple of minutes. Report.
What is considered the largest-ever algal bloom is approaching the Florida coast. The species in question is known as Sargassum, a seaweed that washes to shore and creates an unpleasant smell as it rots. According to Science, “Floating mats of Sargassum seaweed in the center of the North Atlantic were first reported by Christopher Columbus in the 15th century. These mats, although abundant, have until recently been limited and discontinuous. However … since 2011, the mats have increased in density and aerial extent to generate a 8,850-kilometer-long belt that extends from West Africa to the Caribbean Sea and Gulf of Mexico.”
An estimated 3 million gallons of untreated sewage was spilled into Puget Sound. Beaches in the area had to be closed. Many US beaches are being closed this summer because of raw sewage.
Pure Water Annie’s Extra-Simple Instructions for Changing Filter Cartridges in Standard Drinking Water Systems
This article addresses cartridge change for water filters and reverse osmosis systems with standard filter housings, like those pictured below. If you have a proprietary (unique) system like Aquasana or Multipure, you’ll have to figure out how to get the unit apart, but the rest of the instructions apply in a general way.
Some things that you’ll want to have on hand before you start, in addition to the replacement cartridges: a filter wrench, if needed, replacement O rings (though you may not need them), and silicone lubricant, though you won’t need this, either, if the O rings seem sound and sufficiently lubricated. Also, a pan or, better, a towel to catch drips. A flashlight to look for leaks is also nice to have.
To start, turn off the water that goes to the water filter and lock open the faucet. If no water is coming out of the faucet, it’s safe to open the housing to change the cartridge.
With reverse osmosis units you need also to turn off the valve on top of the storage tank. (If your RO unit has no shutoff valve on the tank, you’ll have to let all of the water drain out of the tank. While it’s draining, you’ll have time to reflect on the folly of buying the cheapest RO unit you could find.)
In the countertop unit photograph shown above, the sump is the long part of the housing and sits on top of the base.
Next, open the filter housing(s). The long part of the housing, called the sump, screws off of the short part (the cap for undersink units, the base for countertop). Turn it counterclockwise to remove it. You should have a filter wrench to make the job easy.
Countertop units are often hard to get apart because they aren’t stabilized on a bracket and the wrench doesn’t help. The best strategy with stubborn countertops is to make opening the housing a two-person job, each person using both hands on one part, the cap or the sump. With multi-cartridge units, it’s a good idea to remember, or even mark for future reference, the order that the sumps are arranged in so that you can keep the filters in proper order.
Standard undersink housing. The cap is on top and the bottom part, the sump, screws off counterclockwise.
Remove and replace the cartridges. Except for “candle-style” filters like Doulton, which screw into the cap/base of the housing, cartridges will fall out of the sump when you dump the water into a sink. It’s a good idea with some cartridges to notice which end goes into the sump first. With others it doesn’t matter.
With most radial cartridges (like carbon blocks), both ends of the cartridge are open and there is no up or down to worry about.
For most axial cartridges (like hard-shelled “media” cartridges that contain granular media), up and down do matter. As a general rule, with hard-shelled cartridges there will be only one end gasket. If that’s the case, point the gasket end toward the base or cap.
With axial cartridges, if you get it backward, no water will come out when you turn the filter on. Before replacing the cartridge, it’s a good idea to examine and replace, if necessary, the sump O ring that makes the seal between the cap and seal. This is also a good time to lubricate the O ring with silicone grease, if necessary.
The cartridge on the left is a radial cartridge. The cartridge on the right is an axial cartridge.
Reassemble the unit by replacing the sump onto the cap or base. Be sure the cartridge is aligned in the center of the sump before you tighten. Do not over-tighten. In most cases, hand tightening is fine. If it leaks, you can always give it a final twist with your filter wrench later.
With filters, you are essentially finished at this point.
With the ledge faucet still open, turn on the water and watch for leaks. You’ll hear the hissing and gurgling of air being expelled from the unit. This is normal. Let the water run from the open faucet for three or four minutes to rinse the new cartridge(s) and allow air to escape while you check for leaks. Water may appear milky for awhile, even after rinsing. This is caused by air still trapped in the unit. It’s nothing to worry about, and it will work its way out eventually.
With RO units, you’re not through yet. After you’ve turned on the water, listened to some hissing and gurgling, and determined that there are no leaks, open the valve on top of the storage tank and let all the water run from the tank through the faucet. (Since the inlet is on and the unit is making water, when the tank is empty you’ll still have a trickle or a fast drip coming from the faucet. This is the water the unit is making in real time.)
When the tank has emptied, close the faucet and let the unit begin collecting water in the tank. You can use the water at any time, but you won’t have a lot of water for a few minutes. If your RO unit has no tank valve and you’ve emptied it previously, you’ll have to let the tank fill completely, then empty it again completely to rinse the final filter. While it is emptying, remind yourself again to pay a bit more for a unit with a tank valve the next time around.
Backwashing Sediment Filters FAQ
This piece from the Pure Water Products website is mainly about "multi-media" filters. For residential use, natural zeolite filters have largely replaced multi-media (sand, anthracite, garnet) filters, but the principles of operation are the same. The zeolite filters backwash with less water and filter down to finer micron sizes than multi-media units. You can find a wealth of water treatment information in the Articles Index of the main Pure Water Products website.
How often should sediment filters be backwashed?
On the question of how often a backwashing sediment filter should be backwashed, there is no concrete answer. The common way is simply to guess. If you're guessing, err on the side of too much rather than too little, because excessive sediment buildup can sometimes be irreversible.
The best way to make the when-to-backwash decision is to install pressure gauges before and after the filter. Be sure to backwash before a critical pressure drop is reached.
According to Joseph Harrison (Water Technology, Nov. 2005): "At pressure drop increases of 15 or more psid, the captured suspended solids can begin to form a more compacted filter cake, which may become difficult to break up and remove during backwashing."
What service flow velocities are possible with sediment filters?
As for service flow rates for sediment filters, keep in mind that the best efficiency is at lower flow volumes, and keep in mind especially that recommended flow rates are normally stated in terms of gallons per minute, per square feet of filter surface. That's square feet, not cubic feet. A 10" diameter filter tank may hold 1.5 cubic feet of media, but its surface area in square feet is only about 0.55, a bit over half a square foot. Consider another statement by Harrison:
"Multimedia beds are sometimes effectively operated at flow velocities as high as 20 gpm/ft2, but their best efficiency is perhaps when they are operated in the range of 3 to 5 gpm/ft2" In terms of your 10" X 54" filter, this means that you might push it to an 11 gpm flow, but you'll get best results at 1.65 to 2.75 gpm." (Water Technology, Nov. 2005)
Removal of Edwards Dam, 20th Anniversary
This year marks the 20th Anniversary of the removal of the 160 year old Edwards Dam on the Kennebek River.
Edwards Dam was a hydroelectric dam on the Kennebec River in the U.S. state of Maine. It was located in Augusta, Maine, about 40 miles (64 km) upstream from the Atlantic Ocean. Built in 1837 of timber and concrete, it was 917 feet (280 m) long and 24 feet (7.3 m) high. It is most famous for its removal in 1999, the first removal of a hydroelectric dam by the government against the wishes of the dam owner.
Twenty years ago, the annual run of alewives (a migratory fish essential to the marine food web) up Maine’s Kennebec River was zero. Today, it’s five million — thanks to the removal of Edwards Dam and additional restoration measures upstream. The Kennebec and its web of life have rebounded in many ways since Edwards Dam came down in 1999.
The removal of Edwards Dam was significant because it was the first time the federal government ordered a dam removed because its costs outweighed its benefits. The restoration of the Kennebec sparked a movement for free-flowing rivers in the U.S. and around the world.
According to the dam removal database maintained by American Rivers, 1,605 dams have been removed in the U.S. since 1912. Most of these (1,199) have occurred since the removal of Edwards Dam in 1999. The year with the most dam removals was 2018 (99 dams removed). 2017 was the second most productive year, with 91 dams removed.
The lesson from the Kennebec after twenty years? Dam removal works. The Natural Resources Council of Maine report that since Edwards Dam was removed on July 1, 1999, tens of millions of alewives, blueback herring, striped bass, shad, and other sea-run fish have traveled up the Kennebec River, past the former Edwards Dam, which blocked upstream passage since 1837. Abundant osprey, bald eagles, sturgeon and other wildlife have also returned.
According to American Rivers, “On a basic level, dam removals matter for the specific rivers and ecosystems that are restored to health. But looking at the bigger picture, dam removals also matter in terms of our relationship with all rivers – because with every individual act of restoration we’re creating a new and compelling picture of what the future can look like. We’re spotlighting the benefits that healthy, free-flowing rivers can naturally provide. We’re demonstrating the power of local citizens to drive positive change. And we’re proving that communities can reclaim their rivers and their stories.”
After at least 7 children diagnosed with cancer, parents eye chemical in city’s water
CBS News Report, January 19, 2019
Removing TCE From Residential Water
How Much Nitrate Do Home RO Units Remove?
Dosatron Water-Driven Chemical Injection Pump
The Chlorination of Water in the US
Places to visit for additional information:
Thanks for reading and be sure to check out the next Occasional!